AIDS researchers are cautious about saying the word "cure," but two fascinating cases are enough like each other to publicize what happened. Dr. Timothy Henrich and Dr. Daniel Kuritzkes of Brigham and Women’s Hospital in Boston searched for patients who were infected with HIV and underwent cancer treatment. They found two patients who had stem cell treatments for cancer treatment and were later found to be free of the virus. Unlike most HIV patients, they did not stop taking their retroviral drugs during their cancer treatment.

Both men had endured multiple rounds of treatment for lymphoma, both had stem cell treatments and both had stayed on their HIV drugs throughout. “They went through the transplants on therapy,” Kuritzkes said.

It turns out that was key.

“We found that immediately before the transplant and after the transplant, HIV DNA was in the cells. As the patients’ cells were replaced by the donor cells, the HIV DNA disappeared,” Kuritzkes said. The donor cells, it appears, killed off and replaced the infected cells. And the HIV drugs protected the donor cells while they did it.

One patient is HIV-free two years later, and the other is seemingly uninfected three-and-a-half years later.

“They still have no detectable HIV DNA in their T-cells,” Kuritzkes said. In fact, doctors can’t find any trace of HIV in their bodies -- not in their blood plasma, not when they grow cells in the lab dishes, not by the most sensitive tests.

The cases seem to duplicate what happened to an earlier patient, Timothy Brown, who lost all traces of HIV after a bone marrow transplant five years ago. Brown, known as the famous "Berlin patient," received cells that had a HIV-resistant mutation. He was thought to be the only patient ever cured of HIV, but this latest development gives hope for new therapies. Link -via Kottke